Joanna Trollope, the chairman of the judging panel, praised Miller’s “extraordinary achievement” in weaving together a lyrical tale of war, love and the gods of the ancient world.

She said: “It will be a revelation to lots of people. It is such an extraordinary story. She has been writing it for a decade. It is a very, very seriously written book. It is a big accomplishment - it’s not a rites of passage book.”

The Song of Achilles takes its inspiration from the account in Homer's Iliad of Patroclus, a young Greek prince who was killed on the battlefield during the Trojan War, prompting a huge outpouring of grief from his brother-in-arms, Achilles.

Miller has said about her book: "I wanted to explore who this man was and what he had meant to Achilles that he would be so lost without him."

She has spent the last 10 years teaching Latin, Greek and Shakespeare to American high school students, and currently lives in Cambridge, Massachusetts.

Trollope predicted that the sales boost provided by the Orange Prize will introduce The Song of Achilles to a wide readership.

“The fact that there is a really moving, intense and passionate love affair at the heart of it that you completely believe in - that in a way lures you in,” she said.

“Like all the best books, it is about far more than you think when you begin.”

Half of the six books on this year’s Orange Prize shortlist – which also included Half Blood Blues by Esi Edugyan, Painter of Silence by Georgina Harding, The Forgotten Waltz by Anne Enright and State of Wonder by Ann Patchett - were stories of war with men as main characters.